Study Design, A retrospective study of the long-term results from double-do
or laminoplasty (Kurokawa's method) for patients with myelopathy caused by
ossification of the posterior longitudinal ligament and cervical spondylosi
s was performed.
Objective. To know whether the short-term results from double-door laminopl
asty were maintained over a 10-year period and, if not, the cause of late d
eterioration.
Summary of Background Data. There are few long-term follow-up studies on th
e outcome of laminoplasty for cervical stenotic myelopathy.
Methods. In this study, 35 patients with cervical myelopathy caused by ossi
fication of the posterior longitudinal ligament in the cervical spine and 2
5 patients with cervical spondylotic myelopathy, including 5 patients with
athetoid cerebral palsy, underwent double-door laminoplasty from 1980 throu
gh 1988 and were followed over the next 10 years. The average follow-up per
iod was 153 months (range, 120-200 months) in patients with ossification of
the posterior longitudinal ligament and 156 months (range, 121-218 months)
in patients with cervical spondylotic myelopathy. Neurologic deficits befo
re and after surgery were assessed using a scoring system proposed by the J
apanese Orthopedic Association (JOA score). Patients who showed late deteri
oration received further examination including computed tomography scan and
magnetic resonance imaging of the cervical spine;
Results. In 32 of the patients with ossification of the posterior longitudi
nal ligament and 23 of the patients with cervical spondylotic myelopathy, m
yelopathy improved after surgery. The improvement of Japanese Orthopedic As
sociation scores was maintained up to the final follow-up assessment in 26
of the patients with ossification of the posterior longitudinal ligament an
d 21 of the patients with cervical spondylotic myelopathy. Late neurologic
deterioration occurred in 10 of the patients with ossification of the poste
rior longitudinal ligament an average of 8 years after surgery, and in 4 of
the patients with cervical spondylotic myelopathy, including the 3 patient
s with athetoid cerebral palsy, an average of 11 years after surgery. The m
ain causes of deterioration in patients with ossification of the posterior
longitudinal ligament were a minor trauma in patients with residual cervica
l cord compression caused by ossification of the posterior longitudinal lig
ament and thoracic myelopathy resulting from ossification of the yellow lig
ament in the thoracic spine.
Conclusions. The short-term results of laminoplasty for cervical stenotic m
yelopathy were maintained over 10 years in 78% of the patients with ossific
ation of the posterior longitudinal ligament, and in most of the patients w
ith cervical spondylotic myelopthy, except those with athetoid cerebral pal
sy. Double-door laminoplasty is a reliable procedure for individuals with c
ervical stenotic myelopathy.